Alright, let's work through 3297 times 6390 step by step
3297 × 6390 = 6390 × (3297)
+ 6390 × 7 which equals 44730
+ 6390 × 90 giving us 575100
+ 6390 × 200 resulting in 1278000
+ 6390 × 3000 giving us 19170000

= 21067830
